Place roast on a rack in the pan with the rib side down and the fatty side up.

Roast for 1 hour. Turn off oven. Leave roast in oven but do not open oven door for 2-3 hours. (I give a range because I have had roasts perfect to a bit over-cooked. I would check temperature after 2 hours--don't go over 125°F in final cooking cycle because it will rise another 10 degrees or so during resting phase).

About 30 to 40 minutes before serving time, turn oven to 375°F and reheat the roast. Important: Do not remove roast or re-open the oven door from time roast is put in until ready to serve.

Cover with foil and let stand for 15 minutes before cutting.

In order to satisfy everyone with prime rib. Cook it rare. If anyone wants it done medium, dip their slice in a pot of simmering au jus for 1 minute